Novated lease or buy a car? (paramedic / FBT exception)

I am a currently looking at the option of a novated lease for a used $20k car but am still unsure whether it is the most efficient option. Probably worth noting that I am a public health care worker (paramedic) based in QLD and as such, am elgible for 18k FBT excemption per annum. The numbers seem to be pointing towards salary packaging the car but these numbers only seem best over the term of the lease (ie once the lease is over, the buy out cost is $9K for the leased car but if I bought a car outright, the total resale is mine to keep / reinvest in the next car).

What about an associate lease?
I looked into this last year, basically you have an associate (like a spouse) buy the car. Your employer leases the car of the associate, and takes the cost out of your salary.

Ie there is no finance company involved. So no interest costs.

Advantages are costs are taken out before tax, and you may not have to pay GST on costs (my employer is GST exempt). And FBT might be in your favor.
Disadvantages are the associate has to declare the income, but gets to declare the costs as deductions. (So should be close to neutral.)

Not saying this is what you should do, but I looked into it last year and it looked like a good deal. However because I did not drive the car much, FBT took out a lot of the savings.